Yes, those are crab claws on a samurai helmet. It’s one of 16 pieces of armor that Preston Phro of Rocket News 24 says are from medieval Japan.

I cannot trace the provenance of the crab helmet, but in attempting to do so, I found a book on the history of the samurai written by a fairly well-established journalist. In Samurai: The Last Warrior, John Man does not necessarily address the helmet pictured above. But he does affirm that Japanese helmets of past centuries did include animal designs: